Optional medical device diagnostics (in chronic diarrhea) – depending on the results of history, physical examination, laboratory diagnostics, and obligatory medical device diagnostics – for differential diagnostic workup
- Abdominal sonography (ultrasound examination of abdominal organs) – for basic diagnostics.
- Colonoscopy (colonoscopy) – especially in cases of suspected secretory, inflammatory diarrhea or steatorrhea (fatty stools); with colon biopsies (tissue sampling).
- Sigmoidoscopy (rectosigmoidoscopy, i.e., mirroring of the lower approx. 30-40 cm of the rectum (rectum) and the sigmoid colon (sigmoid loop, sigmoid colon)) – if osmotic diarrhea is suspected (unabsorbed food components or other substances draw water osmotically into the intestinal lumen; occurrence, e.g., in lactose intolerance or lactose intolerance. For example, in lactose intolerance, celiac disease (gluten-sensitive enteropathy), use of laxatives, excessive sorbitol consumption) or to exclude melanosis coli (harmless, patchy dark coloration of the mucosa of the colon; often after long-term use of laxatives).
- Gastroduodenoscopy (mirroring of the stomach and small intestine) with deep small intestinal biopsies – if osmotic diarrhea or steatorrhea is suspected.
- X-ray examination of the small intestine according to Sellink – if inflammatory diarrhea is suspected.
- Magnetic resonance imaging (MRI) according to Sellink (enteroclysma) – if secretory or inflammatory diarrhea is suspected.
